Eisai wins approval for breast cancer drug

Eisai has received marketing approval from the US Food and Drug Administration for Halaven, a new treatment for metastatic breast cancer

Eisai has received marketing approval from the US Food and Drug Administration (FDA) for Halaven (eribulin mesylate), a new treatment for patients with metastatic breast cancer who have received at least two prior chemotherapy regimens, a population for which there are limited existing treatment options.

The injectable drug, which is a synthetic form of a compound derived from a particular type of sea sponge, is believed to work by inhibiting cell growth.

Eisai's marketing application for the drug was supported by a single small study of 762 women with metastatic breast cancer who had received at least two prior chemotherapy regimens for late-stage disease. The US approval stipulates that patients should have received prior anthracycline- and taxane-based chemotherapy for early or late-stage breast cancer before being given Halaven.

The clinical study, which compared Halaven to active controls selected by the patients' oncologists, found that the median overall survival for patients receiving the new drug was 13.1 months compared with 10.6 months for those who received an already marketed single-agent therapy.

Potentially serious side effects observed in the clinical research included anaemia and a decrease in white blood cells. Other common side effects associated with the drug include hair loss, fatigue, nausea, weakness, nerve damage and constipation.

Eisai had originally hoped for a decision on the Halaven marketing application by September 30, the Prescription Drug User Fee Act action date that was set when the company first made its submission. However, the FDA pushed the action date back by several months due to additional information that was needed in the chemistry, manufacturing and controls section of the drug application.

Halaven will compete in the US with Genentech's Xeloda (capecitabine), which is approved for late-stage, refractory breast cancer patients whose disease is resistant to paclitaxel and anthracycline-containing chemotherapy, and with Bristol-Myers Squibb's Ixempra (ixabepilone), which is marketed for patients with late- stage disease after failure of an anthracycline, taxane and Xeloda.